President Trump signed an executive order Monday that suspends travel for 90 days for people from six terror hot spots. Here are some questions and answers provided by the Justice Department to clarify the order, which revises an order signed Jan. 27.

1. Who does the order apply to?

Citizens and nationals of Iran, Libya, Somalia, Sudan, Syria and Yemen who didnít have a visa by 5 p.m. on Jan. 27 cannot enter the United States for 90 days. This restriction applies to unaccompanied children. But the order doesnít apply to legal-permanent residents of the U.S. Ė so-called green card holders. Dual nationals from those countries who are traveling on a passport from a different country arenít affected by the order.

2. When does the order take effect?

March 16 at 12:01 a.m.

3. How were the countries chosen?

Government officials previously identified the six countries as presenting concerns about terrorism. The State Department has designated Iran, Sudan and Syria as state sponsors of terrorism. The Department of Homeland Security has designated Libya, Somalia and Yemen as additional countries of concern.

4. Why isnít Iraq included, as it was in the Jan. 27 order?

The close relationship between the U.S. and the elected government of Iraq, the significant presence of U.S. troops there and Iraqís commitment to fight the Islamic State justified the different treatment, the Justice Department said. Iraq provides more information about its citizens for U.S. immigration decisions than the other countries, Justice said.

5. Does the order revoke previously approved visas?

The order doesnít revoke visas. But the departments of Homeland Security and State can revoke visas for other reasons in the national interest.

6. What about travelers who are already on their way?

Travelers who hold valid visas will be allowed into the U.S., but they must continue to demonstrate that they are admissible.

7. Can travelers from the six countries already in the U.S. leave and return?

Travelers with a single-entry visa arenít allowed to leave and return. But travelers with multiple-entry visas are allowed to enter and leave the U.S. within the effective dates of the visa. If the visa expires while the traveler is overseas, the traveler wonít be allowed to return to the U.S. unless he or she obtains a new visa.

8. What about people who have been granted asylum or refugee status?

Refugees and people granted asylum arenít covered by the travel order. Refugees and people granted asylum who havenít yet arrived in the U.S. will be admitted so long as travel was formally scheduled by the State Department.

9. Are waivers available?

The State Department will consider waivers to visas in conjunction with visa applications. Waivers are granted if the traveler can document that his or her arrival is in the national interest, will not pose a threat to national security, and that denying entry during the suspension period will cause undue hardship.

10. Is Customs and Border Protection coordinating with airlines about the latest travel restrictions?

CBP says it will remain in continuous communication with airlines to provide guidance and answer questions about the order. Airlines routinely check passenger lists before flights against lists provided by CBP to ensure that travelers aren't prohibited from the U.S.